The main purpose of this invention is to provide a walking assistance device with dynamic support by using a sensing device to detect the distances between the device and the user's individual legs. As we know, a walking assistance device related to this invention was designed by a Japanese scholar Ohigata (as showed in FIG. 1). His design included a frame with multiple rollers, a driving motor to control the motion of frame, and a detection setup to detect the distance between the user and the movable frame.
The detection setup in Ohigata's design is to detect the distance between the user's belly and the walking assistance device. When the distance is less than a pre-set value, the control system of the walking assistance device determines that the user is moving forward and commands the motor to activate the rollers to move forward. When the distance is larger than the pre-set value, the control system sends a signal to let the motor rotate in reversed direction, and thereby the walking assistance device moves backward to keep the distance in the preset range.
As showed in FIG. 1, the detecting and operating ways of Ohigata's walking assistance device is not safe for the user. In FIG. 1, status “a” shows that the user is not moving and status “b” shows that the user starts to move forward, and statuses “c” and “d” show that the user does not move but the frame moves forward, which may make user's upper body lean forward. As the motor works normally to move the frame forward, the distance between the user's belly and the detection member is not changed, and the system cannot determine if the user will fall down or not. Statuses “e” and “f” show that the user starts to move but his speed is much slower than that of the rollers. Eventually, the user falls down for that the system cannot detect the situation by simply checking the distance from the user's belly to the detection member.
Furthermore, the rear rollers “g” located on two sides of the frame close to the user are designed to turn freely in every direction. In consequence, the frame does not turn about the user when the user wants to turn. Even worse, when the user falls laterally, the two rollers “g” cannot perform a braking function to stop the sliding.